Patterned bases, and patterning methods

ABSTRACT

Some embodiments include methods of patterning a base. First and second masking features are formed over the base. The first and second masking features include pedestals of carbon-containing material capped with silicon oxynitride. A mask is formed over the second masking features, and the silicon oxynitride caps are removed from the first masking features. Spacers are formed along sidewalls of the first masking features. The mask and the carbon-containing material of the first masking features are removed. Patterns of the spacers and second masking features are transferred into one or more materials of the base to pattern said one or more materials. Some embodiments include patterned bases.

TECHNICAL FIELD

Patterned bases, and patterning methods.

BACKGROUND

Photolithography is commonly utilized during integrated circuitfabrication. Photolithography comprises patterning of photoresist byexposing the photoresist to a pattern of actinic energy, andsubsequently developing the photoresist. The patterned photoresist maythen be used as a mask, and a pattern may be transferred from thephotolithographically-patterned photoresist to underlying materials.

A continuing goal in semiconductor processing is to reduce the size ofindividual electronic components, and to thereby enable smaller anddenser integrated circuitry. A concept commonly referred to as “pitch”can be used to quantify the density of an integrated circuit pattern. Aphotolithographic technique will tend to be constrained by a minimumpitch below which the particular photolithographic technique cannotreliably form features. The minimum pitches associated withphotolithographic techniques present obstacles to continued feature sizereduction in integrated circuit fabrication.

Pitch multiplication, such as pitch doubling, is one proposed method forextending the capabilities of photolithographic techniques beyond theirminimum pitch. The term “pitch-doubling” refers to a process whereby thenumber of features across a given area is doubled relative to the numberof initial photoresist features, and thus a pitch-doubling process willultimately form features on a pitch which is one-half of the pitch ofthe initial photoresist features.

In some applications, it is desired to form different levels of pitchmultiplication across different regions of a semiconductor substrate.For instance, it may be desired to perform pitch-doubling along oneregion of a semiconductor substrate, and to perform pitch-quadruplingalong another region of a semiconductor substrate. It can beadvantageous to utilize common process steps when forming the differentlevels of pitch multiplication in that such may improve economyassociated with a fabrication process. However, it can be difficult todevelop appropriate processing to combine steps of the different levelsof pitch multiplication without also introducing other complexities intothe fabrication process which offset the gains achieved from thecombined steps.

It is desirable to develop new methodologies for pitch multiplication,and to develop processes for applying such methodologies to integratedcircuit fabrication. It is further desirable to develop methodologiesfor pitch multiplication which may efficiently enable multiple commonsteps to be performed while achieving different levels of pitchmultiplication across different regions of a semiconductor substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-14 are diagrammatic cross-sectional views of a semiconductorconstruction shown at various stages of an example embodiment method forpatterning multiple regions of a base.

FIG. 15 is a diagrammatic plan view of a region of the semiconductorconstruction of FIG. 14.

FIGS. 16-21 are diagrammatic cross-sectional views of a semiconductorconstruction shown at various stages of another example embodimentmethod for patterning multiple regions of a base. The processing stageof FIG. 16 may follow that of FIG. 5 in some embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Some embodiments include methods which may be utilized to form multiplepatterns over regions of a base, with some patterns having higherintegration than others (i.e., being more tightly pitched than others).In some embodiments, the more highly integrated patterns may be suitablefor fabricating high-density structures of a memory array (for instance,components of a dynamic random access memory (DRAM) array, components ofa NAND array, etc.) and the other patterns may be suitable forfabricating circuitry peripheral to the memory array. The circuitryperipheral to the memory array may include, for example, controlcircuitry (such as, for example, logic circuitry) that controls accessto memory cells of the memory array during read/write operations, and/ormay include routing circuitry that electrically connects circuitry ofthe memory array to the control circuitry.

Example embodiments are described with reference to FIGS. 1-21.

Referring to FIG. 1, a semiconductor construction 10 is shown tocomprise a base 12 subdivided into regions 5 and 7. Region 5 correspondsto a portion of the base where tightly packed circuitry of a highlyintegrated pattern is to be formed, and region 7 corresponds to aportion of the base where less tightly packed circuitry is to be formed.In some embodiments, region 5 may correspond to a portion of the basewhich will ultimately encompass a memory array (for instance, a DRAMarray or a NAND array), and region 7 may correspond to a portion of thebase which will ultimately encompass circuitry peripheral to the memoryarray (for instance, routing circuitry and/or control circuitry).Although only two regions are shown in FIG. 1, the methodology describedherein may be utilized to form multiple patterns of different pitchesacross multiple regions of a base, and accordingly other embodiments(not shown) may have three or more regions of the base having three ormore different densities of pitches that are to be formed.

The base 12 may comprise, consist essentially of, or consist ofmonocrystalline silicon, and may be referred to as a semiconductorsubstrate, or as a portion of a semiconductor substrate. The terms“semiconductor base,” “semiconductor substrate,” and “semiconductorconstruction” mean any construction comprising semiconductive material,including, but not limited to, bulk semiconductive materials such as asemiconductive wafer (either alone or in assemblies comprising othermaterials), and semiconductive material layers (either alone or inassemblies comprising other materials). The term “substrate” refers toany supporting structure, including, but not limited to, thesemiconductor substrates described above.

Although base 12 is shown to be homogenous, the base may comprisenumerous materials in some embodiments. For instance, base 12 maycorrespond to a semiconductor substrate containing one or more materialsassociated with integrated circuit fabrication. In such embodiments,such materials may correspond to one or more of refractory metalmaterials, barrier materials, diffusion materials, insulator materials,etc.

A stack 14 is over the base 12. The stack 14 includes a first material16, a second material 18, a third material 20, a fourth material 22, anda fifth material 24. In some embodiments, the first material 16 maycomprise, consist essentially of, or consist of silicon nitride; thesecond material 18 may comprise, consist essentially of, or consist ofcarbon; the third material 20 may comprise, consist essentially of, orconsist of silicon oxynitride (e.g., a deposited anti-reflectivecoating); the fourth material 22 may comprise, consist essentially of,or consist of carbon; and the fifth material 24 may comprise, consistessentially of, or consist of silicon oxynitride (e.g., a depositedanti-reflective coating). In some embodiments, materials 20 and 24 maybe referred to as a first silicon oxynitride material and a secondsilicon oxynitride material, respectively.

Although materials 20 and 24 may both comprise silicon oxynitride, theratios of silicon, oxygen and nitrogen may vary in material 24 relativeto material 20. For instance, material 20 may have a greater siliconcontent than material 24. In such embodiments, material 24 may bereadily removed with an etch utilizing dilute hydrofluoric acid (forinstance, hydrofluoric acid diluted about 100 fold with water), whilematerial 20 may be more resistant to such etch than material 24. In someembodiments, material 20 may be heterogeneous, and may, for example,correspond to a so-called bilayer deposited anti-reflective coating;with material 20 comprising an upper portion which is compositionallydifferent than a lower portion. For instance, the upper portion may bemore enriched in silicon than the lower portion.

A patterned mask 26 is formed across the first and second regions 5 and7 of the base 12. The patterned mask comprises a masking material 28.Such masking material may be photolithographically-patterned photoresistin some embodiments.

The patterned mask comprises first masking features 30 over the firstregion 5 of the base, and comprises second masking features 32 over thesecond region 7 of the base. In embodiments in which the maskingmaterial comprises photoresist, the features 30 and 32 may referred toas first and second photoresist features, respectively. The firstmasking features are formed to a first pitch, P₁; and the second maskingfeatures are formed to a second pitch, P₂. The first pitch is shown tobe tighter than the second pitch; and in the shown embodiment P₁ isabout ⅔ of P₂. The illustrated first masking features 30 arerepresentative of a large number of masking features that may be formedacross the region 5 of the base at the first pitch, P₁; and similarlythe illustrated second masking features 32 are representative of a largenumber of masking features that may be formed across the region 7 of thebase at the second pitch, P₂. In some embodiments, the features 30 and32 may be formed in a common photolithography step.

The first masking features are spaced from one another by a gap 40, andthe second masking features are separated from one another by a gap 42.In the shown embodiment, the first masking features have widths of about⅝ P₁, and the second features 32 have widths of about 7/12 P₂. The gap40 has a width of about ⅜ P₁, and the gap 42 has a width of about 5/12P₂.

In the example embodiment processing which follows, the first maskingfeatures 30 are utilized to form a pitch-quadrupled pattern, while thefeatures 32 are utilized to form a pitch-doubled pattern. Thus, features30 are utilized to form relatively a highly integrated pattern, whilefeatures 32 are utilized to pattern a more loosely-spaced pattern. Theshown embodiment enhances the density difference between the patternformed from features 30 relative to that formed from features 32 bystarting with a tighter pitch between features 30 than between 32. Inother embodiments the features 30 and 32 may be formed to a same pitchas one another.

Referring to FIG. 2, the first and second masking features 30 and 32 aresubjected to lateral trimming to remove material from the sides offeatures 30 and 32. In the shown embodiment, about ⅛ P₁ of material 28is removed from each side of the features 30, and about 1/12 P₂ ofmaterial 28 is removed from each side of features 32 (with 1/12 P₂ beingequivalent to ⅛ P₁ in the shown embodiment). The original locations ofthe sides of the features 30 and 32 (i.e., the locations of the sides ofsuch features at the processing stage of FIG. 1) are shown in FIG. 2 indashed-line view to assist the reader in understanding the dimensionalchanges that occurred to the features 30 and 32 through the lateraltrimming. Although the tops of the features 30 and 32 are shown to beunaffected by the lateral trimming, in some embodiments the lateraltrimming conditions may decrease the height of the features and/or mayinduce other changes to the features (e.g., may impose a dome-shape tothe features). For instance, lateral trimming conditions may be chosenwhich isotropically etch the features 30 and 32.

The lateral trimming of features 30 and 32 may be omitted in someembodiments. If the lateral trimming is utilized, such lateral trimmingmay be accomplished with any suitable processing; including, forexample, plasma etching within an inductively coupled reactor.

The lateral trimming reduces the widths of features 30 from thedimension of about ⅝ P₁ of FIG. 1 to a dimension of about ⅜ P₁; andcauses a corresponding increase in the width of gap 40 from thedimension of about ⅜ P₁ of FIG. 1 to a dimension of about ⅝ P₁.Similarly, the lateral trimming reduces the widths of features 32 fromthe dimension of about 7/12 P₂ of FIG. 1 to a dimension of about 5/12P₂; and causes a corresponding increase in the width of gap 42 from thedimension of about 5/12 P₂ of FIG. 1 to a dimension of about 7/12 P₂.

Referring to FIG. 3, spacer material 44 is formed over and between themasking features 30 and 32. The spacer material has a thickness, T, ofabout ⅛ P₁ (i.e., 1/12 P₂). The spacer material may comprise anysuitable composition or combination of compositions, and in someembodiments may comprise, consist essentially of, or consist of silicondioxide. The spacer material may be formed with any suitablemethodology, including, for example, one or both of atomic layerdeposition (ALD) and chemical vapor deposition (CVD). In the shownembodiment, the spacer material is formed conformally over and betweenthe features 30 and 32 so that such spacer material maintains asubstantially common thickness along horizontal and vertical surfaces.

Referring to FIG. 4, spacer material 44 is subjected to an anisotropicetch to form first spacers 46 along the sidewalls of the maskingfeatures 30, and to form second spacers 48 along the sidewalls of thefeatures 32. The spacers 46 and 48 have the same widths as one another,with the spacers 46 being shown to have widths of ⅛ P₁, and with thespacers 48 being shown to have widths of 1/12 P₂.

Referring to FIG. 5, masking features 30 and 32 (FIG. 4) are removed toleave a pattern 50 over region 5, and a pattern 52 over region 7. Thepattern 50 comprises the first spacers 46 spaced-apart from one anotherby intervening gaps 54, and the pattern 52 comprises the second spacers48 spaced-apart from one another by intervening gaps 56. The gaps 54have widths of about ⅜ P₁, and the gaps 56 have widths of about 5/12 P₂.Accordingly, spacers 46 are on a pitch of about ½ P₁, and spacers 48 areon a pitch of about ½ P₂.

In some embodiments, the patterns 50 and 52 may be considered to havebeen formed utilizing the first and second masking features 30 and 32(FIG. 4) as templates.

Referring to FIG. 6, a patterned masking feature 51 is formed overregion 7 of base 12. The masking feature comprises a material 49 whichmay be the same as the material 28 of masking features 30 and 32 (FIG.1). In some embodiments, materials 28 and 49 may comprise photoresist,and feature 51 be referred to as an additional photoresist feature todistinguish it from the features 30 and 32 of FIG. 1. Although oneadditional masking feature 50 is shown, such feature may berepresentative of a large number of additional features which are formedat the processing stage of FIG. 6.

The feature 51 is a lithographic-sized feature, whereas masking features46 and 48 of FIG. 6 are sub-lithographic features. Accordingly, feature51 is shown to have a much larger width along the cross-section of FIG.6 than the features 46 and 48. In some embodiments, the ratio of thewidth of feature 51 relative to the widths of either of the features 46and 48 along the cross-section of FIG. 6 may be at least about 2, atleast about 3, at least about 4, etc.

Referring to FIG. 7, the silicon oxygen nitride material 24 andcarbon-containing material 22 are etched while using the first spacers46, second spacers 48, and masking feature 51 (FIG. 6) as a mask. Suchforms first pedestals 53 under the spacers 46, second pedestals 55 underthe spacers 48, and a third pedestal 57 under the masking feature 51(FIG. 6). The pedestals 53 and 55 comprise capping silicon oxynitride 24over carbon-containing material 22. In the shown embodiment, someresiduals of spacers 46 and 48 remain after etching through materials 22and 24, but in other embodiments the entirety of the spacers 46 and 48may be removed during the etch through materials 22 and 24. Also, in theshown embodiment an entirety of masking feature 51 (FIG. 6) is removedduring the etching through materials 22 and 24, but in other embodimentssome of the masking feature 51 may remain after etching throughmaterials 22 and 24.

In the shown embodiment, the first pedestals 53 are aligned on a pitchwhich is about ½ P₁, and the second pedestals 57 are aligned on a pitchwhich is about ½ P₂. In some embodiments, the pedestals 53 and 55 may bereferred to as first and second masking features, respectively; withsuch masking features comprising pedestals of carbon-containing material22 capped with silicon oxynitride 24. Also, pedestal 57 may be referredto as a third masking feature, which also comprises carbon-containingmaterial 22 capped with silicon oxynitride 24.

Referring to FIG. 8, a protective mask 68 is formed over the pedestals55 and 57, while leaving the pedestals 53 exposed. The protective mask68 comprises a patterned masking material 70. In some embodiments, suchpatterned masking material may correspond tophotolithographically-patterned photoresist. In some embodiments, mask68 may be referred to as a second mask; and the feature 51 together withthe spacers 46 and 48 at the processing stage of FIG. 7 may be referredto as a first mask.

The protective mask 68 has lateral edges 71. Although the mask appearsto have two lateral edges in the side view of FIG. 8, the mask may havea continuous lateral periphery when viewed from above the construction;and thus the lateral edges 71 may be part of a continuous lateralperiphery of the protective mask.

Referring to FIG. 9, residual material of spacers 46 (FIG. 8) is removedfrom over exposed pedestals 53, and silicon oxynitride 24 is alsoremoved from such pedestals. The spacer material 46 and siliconoxynitride 24 may be removed with any suitable etches, with the shownetching being selective for materials 24 and 44 relative to materials 20and 22.

Referring to FIG. 10, anisotropically-etched spacers 74 are formed alongsidewalls of pedestals 53, and anisotropically-etched spacers 76 areformed along the lateral edges 71 of mask 68. In some embodiments,spacers 74 may be referred to as third spacers to distinguish them fromthe first and second spacers 46 and 48 shown in FIG. 6, and spacers 76may be referred to as fourth spacers. In some embodiments, the spacers74 and/or 76 may be referred to as “additional spacers” to distinguishthem from the first and second spacers 46 and 48 of FIG. 6.

The spacers 74 and 76 comprise spacer material 72, and may be formedwith processing analogous to that described above with reference toFIGS. 3 and 4. The spacer material 72 may comprise any suitablecomposition or combination of compositions, and in some embodiments maycomprise, consist essentially of, or consist of silicon oxide.

In the shown embodiment, the spacers 74 and 76 have widths of about ⅛ P₁(which is equivalent to 1/12 P₂ in the embodiment presented herein, asdescribed in FIG. 2).

Although there appear to be two spacers 76 in the side view of FIG. 10,the illustrated spacers 76 may be part of single continuous spacer thatextends along a continuous lateral periphery of the protective mask 68.

The configuration of FIG. 10 shows four pedestals 55 between theopposing spacers 76. Such is for diagrammatic purposes only, and theremay be more or less than the illustrated number of pedestals between theopposing spacers. In some embodiments, there may be many more than fourpedestals 55 between such opposing spacers. Similarly, there may be morethan the single illustrated pedestal 57 in some embodiments.

Although the illustrated embodiment has spacers 74 formed after removingsilicon oxynitride material 24 (FIG. 8) from pedestals 53, in otherembodiments (not shown) such silicon oxynitride material may be removedafter forming the spacers instead of before forming the spacers.

Referring to FIG. 11, the photoresist mask 68 (FIG. 10) is removedtogether with the carbon-containing material 22 of pedestals 53 (FIG.10) utilizing an anisotropic oxidative etch. The anisotropic etchremoves organic material of pedestals 53 and mask 68, while leavingspacers 74, spacers 76, pedestals 55 and pedestal 57 remaining over base12. The anisotropic oxidative etch may comprise any suitable processing,such as, for example, utilization of an O₂ plasma together with asubstrate temperature of at least about 100° C., and a biased chuck. Insome embodiments, the etch may utilize O₂/SO₂; with O₂ being a reactivecomponent and SO₂ being a passivating component that provides a polymer(passivating layer) on sidewalls to alleviate or prevent lateraletching. The anisotropic oxidative etch may be selective relative tosilicon dioxide 44, silicon oxynitride 24 and silicon oxynitride 20, insome embodiments.

The spacers 74 remaining at the processing stage of FIG. 11 are on apitch of about ¼ P₁ in the shown embodiment, and the pedestals 55 are ona pitch of about ½ P₂.

In some embodiments, the spacers 76 of FIG. 11 may be comprised by awall that extends around a portion of the second region 7 of base 12,with such portion including a region between the illustrated spacers 76.In the shown embodiment, the pedestal 57 patterned from the additionalphotoresist feature 51 (FIG. 6) is within such portion.

Referring to FIG. 12, the pattern of spacers 74 (FIG. 11) is transferredinto the underlying material 18 to form a plurality of masking features82 over region 5 of the base; and the pattern of pedestals 55 (FIG. 11)is transferred into the underlying material 18 to form a plurality ofmasking features 84 over region 7 of the base. Also, the pattern ofspacers 76 (FIG. 11) is transferred into the underlying material 18 toform masking features 86, and the pattern of pedestal 57 (FIG. 11) istransferred into underlying material 18 to form a masking feature 87.Although there appear to be two masking features 86 in the side view ofFIG. 10, the illustrated masking features 86 may be part of singlecontinuous masking feature that forms a fence around a portion of region7.

The features 82, 84, 86 and 87 may be formed with any suitableprocessing. For instance, in some embodiments material 20 (FIG. 11)comprises silicon oxynitride, and an etch may be utilized to pattern thesilicon oxynitride into a hard mask (the etch may utilize, for example,CF₄/HBr; with CF₄ being a reactive component and HBr being a passivatingcomponent). The patterned hard mask may be utilized during subsequentetching of material 18 to pattern material 18 into the features 82, 84,86 and 87. In some embodiments, material 18 may comprise carbon andmaterial 16 may comprise silicon nitride, and the etch utilized topattern material 18 may be selective for carbon relative to siliconnitride.

The masking features 82 are on a pitch of about ¼ P₁, and the maskingfeatures 84 are on a pitch of about ½ P₂.

Referring to FIG. 13, the masking features 82, 84, 86 and 87 areutilized to pattern the silicon nitride material 16 and the base 12. Inthe shown embodiment, the masking features 82, 84, 86 and 87 remain overpatterned material 16 and patterned base 12. In other embodiments, themasking features may be utilized to pattern the silicon nitride materialinto a hard mask, and then may be removed while such hard mask isutilized to pattern the underlying base 12.

The embodiment of FIG. 13 shows base 12 as a homogeneous structure.However, as discussed above with reference to FIG. 1, the base maycomprise numerous materials associated with integrated circuitfabrication; including, for example, various conductive materials,semiconductor materials and insulative materials. The pattern formedinto the base may extend into one or more materials of the base topattern such materials. For instance, at least some of the patternformed across region 5 may be utilized to pattern one or more materialsfor fabrication of memory array circuitry (such as, for example, DRAMcircuitry, NAND circuitry, etc.), and at least some of the patternformed across region 7 by masking features 84 and 87 may be utilized topattern one or more materials for fabrication of control circuitryand/or routing circuitry. The masking features 86 may also patternmaterials for fabrication of control circuitry and/or routing circuitry;or, in some embodiments, features 86 may be residual features resultingfrom the processing described herein which create a vestigial (i.e.,functionless) pattern in a semiconductor structure.

Referring to FIG. 14, materials 16 and 18 (FIG. 13) are removed to leavethe patterned base 12. The patterned base has features 90 over region 5formed to a pitch of ¼ P₁, and has features 92 over region 7 formed to apitch of ½ P₂. Thus, the methodology of FIGS. 1-14 may be utilized tofabricate components having a relatively tight pitch across one regionof a base, while also fabricating components having a relatively loosepitch across another region of the base. The patterned base also hasfeatures 93 patterned from the additional photoresist features 51provided at the processing stage of FIG. 6. In some embodiments,features 90, 92 and 93 may comprise identical patterned materials ofbase 12; and in other embodiments at least one of the features maycomprise different materials than at least one other of the features.

The patterned base 12 has features 94 generated from the maskingfeatures 86 (FIG. 13), and corresponding to locations where the spacers76 (FIG. 10) are formed alongside the lateral edges of the protectivemask 68 (FIG. 10). The features 94 may be a pair of separate features(as shown) or may be part of a continuous fence around an area of base12. For instance, FIG. 15 shows a plan view of region 7 in an embodimentin which the features 94 are configured as a fence extending entirelyaround a portion of peripheral region 7. The portion surrounded by suchfence may be referred to as a fenced-in area. The features 92 aregenerically shown in FIG. 15 as a region (designated with a dashed-line)comprising features 92 in order to simplify the drawing. Such features92 may have any suitable configuration, and in some embodiments maycorrespond to routing structures that extend across the fenced-in area.Such routing structures may be electrically conductive interconnectsutilized to couple memory cells formed in the memory region 5 with logiccircuitry, or other circuitry, formed in the peripheral region 7 outsideof the fenced-in area. The routing structures may extend across thefenced-in area, and under the fence 94 to electrically couple with othercircuitry outside of the fenced-in area. The wide features 93 may alsobe part of the circuitry formed in peripheral region 7. In the shownembodiment, features 93 are generically shown in regions comprising thefeatures 93 (designated with dashed-lines). The processing of FIGS. 6-13forms features 93 within the fenced-in area of features 94. Otherprocessing may be utilized in addition to, or alternatively to, suchprocessing to form features 93 outside of the fenced-in area, andaccordingly a region of features 93 is also shown outside of thefenced-in area in FIG. 15. Example processing which may be utilized forforming features 93 outside of the fenced-in area 94 is discussed belowwith reference to FIGS. 16-21.

The feature 93 is wider than the other features along the cross-sectionof FIG. 14 due to the feature 93 having been etched under a lithographicpattern (51 of FIG. 6), while the features 90, 92 and 94 were etchedunder sub-lithographic patterns (46 and 48 of FIGS. 6, and 76 of FIG.11). In some embodiments, features 90, 92 and 94 may comprise about asame cross-sectional width as one another along the cross-section ofFIG. 14 (i.e., may comprise about the same lateral dimensions as oneanother along such cross-section), while feature 93 has across-sectional width at least about double the individual widths offeatures 90, 92 and 94 (or at least about triple, at least aboutfour-times, etc., in various example embodiments). In some embodiments,features 92 may be referred to as first patterned features formed withinthe fenced-in area defined by the fence 94, with such features havingabout the same lateral dimension as the fence along a cross-section (forinstance, the cross-section of FIG. 14). In such embodiments, feature 93may be referred to as a second patterned feature inside of the fenced-inarea and having a lateral dimension along the cross-section which is atleast about double the lateral dimension of the fence (or at least abouttriple, at least about four-times, etc., in various exampleembodiments). The feature 93 may be representative of a plurality offeatures. In some embodiments, all of the features 93 may be inside ofthe fenced-in area defined by the fence 94, and in other embodimentsonly some of the features 93 may be inside of such fenced-area.

The fence 94 of FIGS. 14 and 15 may comprise any suitable materials ofbase 12, and in some embodiments may comprise electrically insulativematerial; such as, for example, silicon dioxide or silicon nitride. Insome embodiments, the patterned features 92 comprise one or morepatterned materials of base 12, and the fence 94 comprises identicalpatterned materials as the patterned features. In other words, thematerials of the patterned features 92 extend to the locations where thefence 94 is formed and are incorporated into such fence. In otherembodiments, the patterned features 92 comprise one or more patternedmaterials of base 12 that are not comprised by the fence 94 and/or thefence comprises one or more materials that are not comprised by thepatterned features. In other words, one or more materials of thepatterned features 92 do not extend to the locations where the fence 94is formed and/or one or more materials incorporated into the fence 94 donot extend across locations where the patterned features 92 are formed.Similarly, features 93 may or may not comprise identical patternedmaterials as one or both of features 92 and fence 94.

In the shown embodiment of FIGS. 14 and 15, the fence 94 is associatedwith region 7 of the base, but it is to be understood that the fence 94may be associated with other regions of the base depending on theconfiguration of the protective mask 68 (FIG. 10). The fence 94 maycorrespond to a patterned component of an integrated circuit in someembodiments, or may correspond to a vestigial structure that resultsfrom tag-along patterning associated with the spacers 76 (FIG. 11)through the process stages of FIGS. 12-14 in other embodiments.

FIGS. 13 and 14 illustrate an embodiment in which masking featurepatterns are transferred into one or more materials of an underlyingbase by utilizing the masking features to pattern an etch. In otherembodiments, masking feature patterns may be transferred into one ormore materials of an underlying base by utilizing the masking featuresto pattern a dopant implant into the underlying base.

As discussed above, the processing of FIGS. 6-15 forms features 93within a fenced-in area defined by the fence 94 of FIGS. 14 and 15.Other processing may be utilized to form at least some features 93outside of the fenced-in area. FIGS. 16-21 describe an exampleembodiment method for forming at least some of the features 93 outsideof such fenced-in area.

Referring to FIG. 16, a construction 10 a is shown at a processing stagesubsequent to that of FIG. 5. The first pedestals 53 and secondpedestals 55 have been formed over regions 5 and 7, respectively,utilizing processing analogous to that described above with reference toFIG. 7. In the shown embodiment, some of the spacer material 44 remainsover pedestals 53 and 55. In other embodiments, an entirety of suchspacer material may be removed during formation of the pedestals 53 and57.

Referring to FIG. 17, the mask 68 is formed over pedestals 55. Such maskmay be formed utilizing processing analogous to that described abovewith reference to FIG. 8.

Referring to FIG. 18, residual spacer material 44 and silicon oxynitride24 (FIG. 17) are removed from over exposed pedestals 53; andanisotropically-etched spacers 74 and 76 are formed along sidewalls ofpedestals 53 and along the lateral edges 71 of mask 68, respectively. Insome embodiments, spacers 74 may be referred to as third spacers andspacers 76 may be referred to as fourth spacers. The processing of FIG.18 may be conducted analogously to the above-discussed processing ofFIGS. 9 and 10. In some embodiments, the residual spacer material 44 andsilicon oxynitride 24 (FIG. 17) may be removed before formation ofanisotropically-etched spacers 74 and 76, and in other embodiments suchresidual spacer material and silicon oxynitride may be removed afterformation of the anisotropically-etched spacers 74 and 76.

The spacers 74 and 76 have widths of about ⅛ P₁ (which is equivalent to1/12 P₂ in the embodiment presented herein, as described in FIG. 2).

Referring to FIG. 19, the photoresist mask 68 (FIG. 18) is removedtogether with the carbon-containing material 22 of pedestals 53 (FIG.18) utilizing an anisotropic oxidative etch analogous to the etchdescribed above with reference to FIG. 11.

The spacers 74 remaining at the processing stage of FIG. 19 are on apitch of about ¼ P₁ in the shown embodiment, and the pedestals 55 are ona pitch of about ½ P₂.

A patterned masking feature 51 is formed over region 7 of base 12utilizing processing analogous to that described above with reference toFIG. 6. The masking feature comprises a material 49 which may bephotoresist in some embodiments. Although one additional masking feature51 is shown, such feature may be representative of a large number ofadditional features which are formed at the processing stage of FIG. 19.

In some embodiments, the spacers 76 of FIG. 19 may be comprised by awall that extends around a portion of the second region 7 of base 12,with such portion including a region between the illustrated spacers 76.In the shown embodiment, patterned masking feature 51 is formed outsideof such walled-in portion. In other embodiments, the patterned maskingfeature 51 may be formed within such walled-in portion (utilizing, forexample, the processing of FIGS. 6-14) alternatively to, or additionallyto, being formed outside of such wall-in portion.

The feature 51 is a lithographic-sized feature, whereas spacers 74,spacers 76, and pedestals 55 of FIG. 19 are sub-lithographic features.Accordingly, feature 51 is shown to have a much larger width along thecross-section of FIG. 19 than the spacers 74, spacers 76 and pedestals55. In some embodiments, the width of feature 51 may be at least abouttwice as large as the widths of spacers 74, spacers 76 and pedestals 55along the cross-section of FIG. 19 (or at least about three-times aslarge, at least about four-times as large, etc.).

Referring to FIG. 20, the pattern of spacers 74 (FIG. 19) is transferredinto the underlying material 18 to form a plurality of masking features82 over region 5 of the base; and the pattern of pedestals 55 (FIG. 19)is transferred into the underlying material 18 to form a plurality ofmasking features 84 over region 7 of the base. Also, the pattern ofspacers 76 (FIG. 19) is transferred into the underlying material 18 toform masking features 86, and the pattern of feature 51 (FIG. 19) istransferred into underlying material 18 to form a masking feature 87.Although there appear to be two masking features 86 in the side view ofFIG. 20, the illustrated masking features 86 may be part of singlecontinuous masking feature that forms a fence around a portion of region7, analogous to the description provided above with reference to FIG.12. The embodiment of FIG. 20 differs from that of FIG. 12 in thatfeature 87 is outward of the fenced-in area between features 86, ratherthan being within such fenced-in area.

The features 82, 84, 86 and 87 may be formed with any suitableprocessing; such as, for example, processing analogous to that describedabove with reference to FIG. 12.

The masking features 82 have a pitch which is about ¼ P₁, and themasking features 84 have a pitch which is about ½ P₂.

Referring to FIG. 21, the masking features 82, 84, 86 and 87 areutilized to form structures 90, 92, 94 and 93, respectively in base 12utilizing processing analogous to that described above with reference toFIGS. 13 and 14.

The embodiment of FIG. 21 shows base 12 as a homogeneous structure.However, as discussed above with reference to FIG. 1, the base maycomprise numerous materials associated with integrated circuitfabrication; including, for example, various conductive materials,semiconductor materials and insulative materials. The pattern formedinto the base may extend into one or more materials of the base topattern such materials. For instance, at least some of the patternformed across region 5 may be utilized to pattern one or more materialsfor fabrication of memory array circuitry (such as, for example, DRAMcircuitry, NAND circuitry, etc.), and at least some of the patternformed across region 7 by may be utilized to pattern one or morematerials for fabrication of control circuitry and/or routing circuitry.

In some embodiments, features 90, 92, 93 and 94 may comprise identicalpatterned materials of base 12; and in other embodiments at least one ofthe features may comprise different materials than at least one other ofthe features.

The features 94 of FIG. 21 may be part of a continuous fence around anarea of base 12, analogous to the shown fenced-in area of FIG. 15. Theembodiment of FIG. 21 has the wide features 93 outside of such fenced-inarea.

In some embodiments, features 92 may be referred to as first patternedfeatures formed within the fenced-in area defined by the fence 94, withsuch features having about the same lateral dimension as the fence alonga cross-section (for instance, the cross-section of FIG. 21). In suchembodiments, feature 93 may be referred to as a second patterned featureoutside of the fenced-in area and having a lateral dimension along thecross-section which is at least about double the lateral dimension ofthe fence (or at least about triple, at least about four-times, etc., invarious embodiments). The feature 93 may be representative of aplurality of features. In some embodiments, all of the features 93 maybe outside of the fenced-in area defined by the fence 94, and in otherembodiments only some of the features 93 may be outside of suchfenced-area.

The particular orientation of the various embodiments in the drawings isfor illustrative purposes only, and the embodiments may be rotatedrelative to the shown orientations in some applications. The descriptionprovided herein, and the claims that follow, pertain to any structuresthat have the described relationships between various features,regardless of whether the structures are in the particular orientationof the drawings, or are rotated relative to such orientation.

The cross-sectional views of the accompanying illustrations only showfeatures within the planes of the cross-sections, and do not showmaterials behind the planes of the cross-sections in order to simplifythe drawings.

For purposes of interpreting this disclosure and the claims that follow,a first material is considered to be “selectively removed” relative to asecond material if the first material is removed at a faster rate thanthe second material; which can include, but is not limited to,embodiments in which the first material is removed under conditionswhich are 100 percent selective for the first material relative to thesecond material.

When a structure is referred to above as being “on” or “against” anotherstructure, it can be directly on the other structure or interveningstructures may also be present. In contrast, when a structure isreferred to as being “directly on” or “directly against” anotherstructure, there are no intervening structures present. When a structureis referred to as being “connected” or “coupled” to another structure,it can be directly connected or coupled to the other structure, orintervening structures may be present. In contrast, when a structure isreferred to as being “directly connected” or “directly coupled” toanother structure, there are no intervening structures present.

Some embodiments include methods of patterning a base. First maskingfeatures are formed over a first region of the base, and second maskingfeatures are formed over a second region of the base. The first andsecond masking features comprise pedestals of carbon-containing materialcapped with silicon oxynitride. A protective mask is formed over thesecond masking features while leaving the first masking featuresexposed. The silicon oxynitride caps are removed from the first maskingfeatures while the protective mask remains over the second maskingfeatures. Spacers are formed along sidewalls of the first maskingfeatures. The protective mask and the carbon-containing material of thefirst masking features are removed while leaving the second maskingfeatures remaining over the second region and while leaving the spacersremaining over the first region. Patterns of the spacers and secondmasking features are transferred into one or more materials of the baseto pattern said one or more materials.

Some embodiments include methods of patterning multiple regions of abase. A stack is formed over the base. The stack comprises, in ascendingorder from the base, a first silicon oxynitride material,carbon-containing material and a second silicon oxynitride material. Thefirst silicon oxynitride material has a greater silicon content than thesecond silicon oxynitride material. Photoresist features are formed overthe stack. Anisotropically-etched spacers are formed along sidewalls ofthe photoresist features. The photoresist features are removed whileleaving the anisotropically-etched spacers over the stack. Theanisotropically-etched spacers over a first region of the base beingfirst spacers, and the anisotropically-etched spacers over a secondregion of the base being second spacers. The second silicon oxynitridematerial and the carbon-containing material are etched while using thefirst and second spacers as a first mask. The etching forms firstpedestals over the first region, and forms second pedestals over thesecond region. A second mask is formed over the second pedestals and notover the first pedestals. While the second mask is over the secondpedestals, the second silicon oxynitride material is removed from thefirst pedestals and additional spacers are formed along sidewalls of thefirst pedestals. The second mask and the carbon-containing material ofthe first pedestals are removed while leaving the second pedestals andadditional spacers remaining over the base. Patterns of the additionalspacers and the second pedestals are transferred into one or morematerials of the base to pattern said one or more materials.

Some embodiments include methods of patterning multiple regions of abase. A stack is formed over the base. The stack comprises, in ascendingorder from the base, a first silicon oxynitride material,carbon-containing material, and a second silicon oxynitride material.The first silicon oxynitride material has a greater silicon content thanthe second silicon oxynitride material. First photoresist features areformed over the stack. Anisotropically-etched spacers are formed alongsidewalls of the first photoresist features. The first photoresistfeatures are removed while leaving the anisotropically-etched spacersover the stack. The anisotropically-etched spacers over a first regionof the base are first spacers, and the anisotropically-etched spacersover a second region of the base are second spacers. After removing thefirst photoresist features, one or more additional photoresist featuresare formed over the stack. The second silicon oxynitride material andthe carbon-containing material are etched while using the first andsecond spacers and the one or more additional photoresist features as afirst mask. The etching forms first pedestals over the first region,forms second pedestals over the second region, and forms one or morethird pedestals from the second silicon oxynitride material andcarbon-containing material under the one or more additional photoresistfeatures. A second mask is formed over the second and third pedestals,and not over the first pedestals. While the second mask is in place, thesecond silicon oxynitride material is removed from the first pedestals,and additional spacers are formed along sidewalls of the firstpedestals. The second mask and the carbon-containing material of thefirst pedestals are removed while leaving the second and third pedestalsremaining over the base and while leaving the additional spacersremaining over the first region. Patterns of the additional spacers, andthe second and third pedestals are transferred into one or morematerials of the base to pattern said one or more materials.

Some embodiments include methods of patterning multiple regions of abase. A stack is formed over the base. The stack comprises, in ascendingorder from the base, a first silicon oxynitride material,carbon-containing material, and a second silicon oxynitride material.The first silicon oxynitride material has a greater silicon content thanthe second silicon oxynitride material. First photoresist features areformed over the stack. Anisotropically-etched spacers are formed alongsidewalls of the first photoresist features. The first photoresistfeatures are removed while leaving the anisotropically-etched spacersover the stack. The anisotropically-etched spacers over a first regionof the base are first spacers, and the anisotropically-etched spacersover a second region of the base are second spacers. The second siliconoxynitride material and the carbon-containing material are etched whileusing the first and second spacers as a first mask. The etching formsfirst pedestals over the first region, and forms second pedestals overthe second region. A second mask is formed over the second pedestals andnot over the first pedestals. The second mask has lateral edges. Whilethe second mask is over the second pedestals, the second siliconoxynitride material is removed from the first pedestals. Third spacersare formed along sidewalls of the first pedestals, and fourth spacersare formed along the lateral edges of the second mask. The second maskand the carbon-containing material of the first pedestals are removedwhile leaving the third spacers, fourth spacers, and second pedestalsremaining over the base. After the second mask is removed, one or moreadditional photoresist features are formed over the stack. Patterns ofthe additional photoresist features, the second pedestals, and the thirdand fourth spacers are transferred into one or more materials of thebase to pattern said one or more materials.

Some embodiments include a patterned base having a fence around an areaof the base. The area of the base surrounded by the fence is a fenced-inarea. The fence has a lateral dimension along a cross-section. Aplurality of first patterned features are within the fenced-in area andhave lateral dimensions along the cross-section that are about the sameas the lateral dimension of the fence. One or more second patternedfeatures are outside and/or inside of the fenced-in area and havelateral dimensions along the cross-section at least about double thelateral dimension of the fence.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

I claim:
 1. A method of patterning a base, comprising: forming firstmasking features over a first region of the base, and forming secondmasking features over a second region of the base; the first and secondmasking features comprising pedestals of carbon-containing materialcapped with silicon oxynitride; forming a protective mask over thesecond masking features while leaving the first masking featuresexposed; removing the silicon oxynitride caps from the first maskingfeatures while the protective mask remains over the second maskingfeatures; forming spacers along sidewalls of the first masking features;removing the protective mask and the carbon-containing material of thefirst masking features while leaving the second masking featuresremaining over the second region and while leaving the spacers remainingover the first region; and transferring patterns of the spacers andsecond masking features into one or more materials of the base topattern said one or more materials.
 2. The method of claim 1 wherein theprotective mask and carbon-containing material of the first maskingfeatures are removed with an anisotropic oxidative etch.
 3. The methodof claim 1 wherein the protective mask and carbon-containing material ofthe first masking features are removed utilizing an O₂ plasma.
 4. Themethod of claim 1 wherein: the protective mask has lateral edges; thespacers are first spacers, and second spacers are formed along thelateral edges of the protective mask while the first spacers are formed;the second spacers remain over the base after the protective mask isremoved; and the patterns of the second spacers are transferred into thebase together with the patterns of the first spacers and second maskingfeatures.
 5. The method of claim 4 wherein the first and second spacersare formed after removing the silicon oxynitride caps from the firstmasking features.
 6. The method of claim 4 wherein the protective maskcomprises carbon, the first and second spacers comprises silicondioxide, and the protective mask is removed with an anisotropic etchselective for the protective mask relative to the silicon oxynitridecaps over the second masking features and selective for the protectivemask relative to the first and second spacers.
 7. The method of claim 6wherein the protective mask comprises photolithographically-patternedphotoresist.
 8. A base patterned by the method of claim
 1. 9. A methodof patterning multiple regions of a base, comprising: forming a stackover the base; said stack comprising, in ascending order from the base,a first silicon oxynitride material, carbon-containing material and asecond silicon oxynitride material; the first silicon oxynitridematerial having a greater silicon content than the second siliconoxynitride material; forming photoresist features over the stack;forming anisotropically-etched spacers along sidewalls of thephotoresist features; removing the photoresist features while leavingthe anisotropically-etched spacers over the stack; theanisotropically-etched spacers over a first region of the base beingfirst spacers, and the anisotropically-etched spacers over a secondregion of the base being second spacers; etching through the secondsilicon oxynitride material and the carbon-containing material whileusing the first and second spacers as a first mask; the etching formingfirst pedestals over the first region from the second silicon oxynitrideand carbon-containing material under the first spacers, and formingsecond pedestals over the second region from the second siliconoxynitride material and carbon-containing material under the secondspacers; forming a second mask over the second pedestals and not overthe first pedestals; while the second mask is over the second pedestals,removing the second silicon oxynitride material from the first pedestalsand forming additional spacers along sidewalls of the first pedestals;removing the second mask and the carbon-containing material of the firstpedestals while leaving the second pedestals and additional spacersremaining over the base; and transferring patterns of the additionalspacers and the second pedestals into one or more materials of the baseto pattern said one or more materials.
 10. The method of claim 9 furthercomprising removing only a portion of the second spacers from over thesecond pedestals prior to forming the second mask.
 11. The method ofclaim 9 further comprising removing an entirety of the second spacersfrom over second pedestals prior to forming the second mask.
 12. Themethod of claim 9 wherein the second mask comprisesphotolithographically-patterned photoresist.
 13. The method of claim 9wherein the photoresist features are first photoresist features, andfurther comprising forming additional photoresist features over the baseafter forming the first and second pedestals.
 14. The method of claim 13wherein patterns of the additional photoresist features are transferredinto the one or more materials of the base during transfer of thepatterns of the additional spacers and the second pedestals into thebase.
 15. The method of claim 14 wherein the additional photoresistfeatures are formed prior to forming the second mask.
 16. The method ofclaim 14 wherein the additional photoresist features are formed afterremoving the second mask.
 17. The method of claim 14 wherein theadditional spacers pattern components of a memory array within the oneor more materials of the base, and wherein the second pedestals andadditional photoresist features pattern components peripheral to thememory array within the one or more materials of the base.
 18. A methodof patterning multiple regions of a base, comprising: forming a stackover the base; the stack comprising, in ascending order from the base, afirst silicon oxynitride material, carbon-containing material, and asecond silicon oxynitride material; the first silicon oxynitridematerial having a greater silicon content than the second siliconoxynitride material; forming first photoresist features over the stack;forming anisotropically-etched spacers along sidewalls of the firstphotoresist features; removing the first photoresist features whileleaving the anisotropically-etched spacers over the stack; theanisotropically-etched spacers over a first region of the base beingfirst spacers, and the anisotropically-etched spacers over a secondregion of the base being second spacers; after removing the firstphotoresist features, forming one or more additional photoresistfeatures over the stack; etching through the second silicon oxynitridematerial and the carbon-containing material while using the first andsecond spacers and the one or more additional photoresist features as afirst mask; the etching forming first pedestals over the first regionfrom the second silicon oxynitride and carbon-containing material underthe first spacers, forming second pedestals over the second region fromthe second silicon oxynitride material and carbon-containing materialunder the second spacers, and forming one or more third pedestals fromthe second silicon oxynitride material and carbon-containing materialunder the one or more additional photoresist features; forming a secondmask over the second and third pedestals, and not over the firstpedestals; while the second mask is over the second and third pedestals,removing the second silicon oxynitride material from the firstpedestals; forming additional spacers along sidewalls of the firstpedestals; removing the second mask and the carbon-containing materialof the first pedestals while leaving the second and third pedestalsremaining over the base, and while leaving the additional spacersremaining over the first region; and transferring patterns of theadditional spacers, and the second and third pedestals into one or morematerials of the base to pattern said one or more materials.
 19. Themethod of claim 18 wherein the additional spacers are formed afterremoving the second silicon oxynitride material from the firstpedestals.
 20. A method of patterning multiple regions of a base,comprising: forming a stack over the base; the stack comprising, inascending order from the base, a first silicon oxynitride material,carbon-containing material, and a second silicon oxynitride material;the first silicon oxynitride material having a greater silicon contentthan the second silicon oxynitride material; forming first photoresistfeatures over the stack; forming anisotropically-etched spacers alongsidewalls of the first photoresist features; removing the firstphotoresist features while leaving the anisotropically-etched spacersover the stack; the anisotropically-etched spacers over a first regionof the base being first spacers, and the anisotropically-etched spacersover a second region of the base being second spacers; etching throughthe second silicon oxynitride material and the carbon-containingmaterial while using the first and second spacers as a first mask; theetching forming first pedestals over the first region from the secondsilicon oxynitride and carbon-containing material under the firstspacers, and forming second pedestals over the second region from thesecond silicon oxynitride material and carbon-containing material underthe second spacers; forming a second mask over the second pedestals, andnot over the first pedestals; the second mask having lateral edges;while the second mask is over the second pedestals, removing the secondsilicon oxynitride material from the first pedestals; forming thirdspacers along sidewalls of the first pedestals and forming fourthspacers along the lateral edges of the second mask; removing the secondmask and the carbon-containing material of the first pedestals whileleaving the third spacers, fourth spacers, and second pedestalsremaining over the base; after removing the second mask, forming one ormore additional photoresist features over the stack; transferringpatterns of the additional photoresist features, the second pedestals,and the third and fourth spacers into one or more materials of the baseto pattern said one or more materials.
 21. The method of claim 20wherein the fourth spacers form a wall around a portion of the secondregion of the base, and wherein one or more of the additionalphotoresist features are formed outside of such wall.
 22. The method ofclaim 20 wherein the fourth spacers form a wall around a portion thesecond region of the base, and wherein one or more of the additionalphotoresist features are formed inside of such wall.
 23. The method ofclaim 20 wherein the photoresist features formed over the first regionare at a tighter pitch than the photoresist features formed over thesecond region.
 24. A patterned base, comprising: a fence around an areaof the base, the area of the base surrounded by the fence being afenced-in area, the fence having a lateral dimension along across-section; a plurality of first patterned features within thefenced-in area and having lateral dimensions along the cross-sectionthat are about the same as the lateral dimension of the fence; and oneor more second patterned features outside and/or inside of the fenced-inarea and having lateral dimensions along the cross-section at leastabout double the lateral dimension of the fence.
 25. The patterned baseof claim 24 wherein at least some of the second patterned features areoutside of the fenced-in area.
 26. The patterned base of claim 24wherein all of the second patterned features are outside of thefenced-in area.
 27. The patterned base of claim 24 wherein at least someof the second patterned features are inside of the fenced-in area. 28.The patterned base of claim 24 wherein all of the second patternedfeatures are inside of the fenced-in area.
 29. The patterned base ofclaim 24 wherein the first and second patterned features comprise one ormore patterned materials, and wherein the fence comprises identicalpatterned materials as the first and second patterned features.